Objective: To explore a new efficient purification method of hepatocellular carcinoma (HCC) stem cells and identify their features.
Methods: Human hepatocellular carcinoma cell line SMMC-7721 was cultured in sphere-culture system of polyhedra-treated dish and tumor stem cell specific medium. Upon the formation of cellular sphere, the cells were inoculated subcutaneously into immunocompromised mice and received the interventions of different concentrations of cisplatin. Then the drug-resistant cells were purified and re-cultured in TSC medium. Finally the stem cell markers and tumor stem cell markers were determined through real-time polymerase chain reaction (PCR), immunofluorescence method and flow cytometry.
Results: Through the double filter of TSC medium and cisplatin-resistance, SMMC-7721 stem cells could be grown in a suspended form and formed spheres in TSC medium. The stem cell markers (NANOG, OCT-4, SOX-2 and Notch) and tumor stem cell markers (CD24, 90.0%; CD133, 6.1%; CD90, 4.8%) were all over-expressed in purified cancer stem cells as compared with ordinary cells. And the over-expression of CD24 was the most obvious.
Conclusions: The combination of in vitro cell culture with TSC medium, in vivo proliferation and cisplatin resistance test is a new efficient method of purifying hepatocellular carcinoma stem cells. Tumor stem cell with stem cell characteristics and an over-expression of CD24 may be cloned from SMMC-7721.